how to refresh listview on a fragment

I need your help

I have a listview (I fill it with SQLite) on a fragment, this fragment is on pageViewer with Swipe. Also, There is a button on ActionBar, when I click on the button, this download the data (external SQLServer) and I sync with SQLite.

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My question:

How can when I click on the button the listview refresh/update visually it on the activity?